Non-Chiral S-Matrix of N=4 Super Yang-Mills
Yu-tin Huang
TL;DR
The paper presents a non-chiral formulation of the S-matrix for four-dimensional $\, ext{N}=4$ SYM by using Hatsuda–Siegel projective (half-coset) superspace, showing that the non-chiral dual superconformal symmetry arises as a natural uplift from six dimensions. By mapping dual projective coordinates to on-shell variables $(\,\lambda,\tilde{\lambda},\eta,\bar{\eta})$ and performing half-Fourier transforms, the authors construct explicit non-chiral representations for five-point and general $n$-point MHV and anti-MHV amplitudes, and demonstrate that these data uplift to six dimensions, corresponding to massive 4D amplitudes. They spell out the Yangian structure, with 16 level-1 generators emerging from the non-chiral construction and the rest generated by commutators with the original superconformal algebra. The work also develops ambi-momentum twistor space to express non-chiral amplitudes in a form manifestly cyclic and dual-conformal, and discusses the partial DSC covariance and the role of $y$-coords, pointing toward a full six-dimensional embedding as a future challenge. Overall, the non-chiral approach provides a robust bridge between massless 4D amplitudes, their massive 4D descendants, and fully six-dimensional DSC symmetry, with potential implications for Wilson loop dualities and ABJM-like structures.
Abstract
We discuss the construction of non-chiral S-matrix of four-dimensional N=4 super Yang-Mills using a non-chiral superspace. This construction utilizes the non-chiral representation of dual superconformal symmetry, which is the natural representation from the point of view of the six-dimensional parent theory. The superspace in discussion is projective superspace constructed by Hatsuda and Siegel, and is based on a half coset U(2,2|4)/U(1,1|2)^2_+. We obtain the non-chiral representation of the five-point and general n-point MHV and anti-MHV amplitude. The non-chiral formulation can be straightforwardly lifted to six dimensions, which is equivalent to massive amplitudes in four dimensions.
